Hello Everyone, I try to make a low pass operation on my data set which has 1kHz sampling rate. When I try to make fft power spectrum, I always see the first dominant peak and cannot observe the other details clearly. My advisor wants from me to use a low pass filter to eliminate this highly dominant peak of the power spectrum. I used fdatool with Fp = 800, Fs = 1600, Fsampling = 10000, Apass = 1dB, Astop = 80dB. The filter has the freq response as shown in Fig 1.
As I apply this filter to my data set, which gives the results like below in Fig 2. The green line is the original data set and the blue which has another unwanted occured peak one is the filtered data. This peak is not related with anything. It came out after filtering. Simply, I need to get rid of this with a proper filter design. Can you help me with this please ?